US3914680A
Expired / Lapsed
US
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Static inverter
Assignee: General Electric Co
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Filing: 1975-01-17
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Granted: 1975-10-21
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Expires: 1995-01-17
Abstract
Abstract A static inverter is disclosed for d.c. to a.c. conversion comprising a pair of switching semiconductor devices and a power transformer having primary, secondary and feedback windings associated with a linear magnetic core. A small perforation partitions the core into two localized branches at the same time forming a small magnetic loop encircling the perforation. Both power windings encircle the full core, while the feedback windings are associated with one of the branches. One branch is designed to saturate before the other branch and thus before full core saturation. Saturation of one branch affects the feedback derived in a winding encircling either branch - decreasing the feedback in the winding encircling the saturated branch and increasing the feedback in the winding encircling the branch remaining unsaturated. The arrangement permits cyclical control of the feedback to avoid full core saturation and thus avoids overstressing the switching devices. The feedback windings are typically single turn windings. The introduction of an additional single turn primary winding connected in the primary power circuit creates a virtual current transformer utilizing the small magnetic loop which makes the feedback drive proportional to load current. The arrangement is reliable and economical in its use of materials.
Inventors
- 👤 Joseph P Hesler
- 👤 Samuel M Korzekwa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 06:43
CPC Classifications
H; H02; H02M; H02M7/00; H02M7/42; H02M7/44; H02M7/48; H02M7/53; H02M7/537; H02M7/5383; H02M7/53846; H02M7/53862
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
229 words
A static inverter comprising: a. input terminals for connection to a source of d.c. potentials, b. a pair of semiconductor power switching devices, each semiconductor device having a pair of input electrodes and an output electrode, c. a transformer having 1. a core of substantially linear magnetic material having a closed magnetic path of approximately uniform cross-section with a small aperture introduced into said core to partition the magnetic cross section in a localized region into two branches between which the flux may be steered with a magnetomotive force, 2. a pair of primary power windings encircling the full core cross-section, each coupled between an output electrode of one of said semiconductor devices and said source terminals for generating an alternating flux in said core as said devices are switched, 3. a secondary power winding encircling the full core crosssection to derive an alternating voltage output, 4. first feedback winding means associated with said core and coupled to said input electrodes to provide self-regenerative feedback to each semiconductor device and cross-coupling between semiconductor devices to facilitate commutation; second feedback winding means associated with said core and coupled to said input electrodes to provide self-degenerative feedback to each semiconductor device; at least one of said feedback winding means being coupled through said aperture to one branch of said core to make the feedback dependent upon saturation of a partitioned branch.
Claim 2
Dependent Claim
229 words
A static inverter comprising: a. input terminals for connection to a source of d.c. potentials, b. a pair of semiconductor power switching devices, each semiconductor device having a pair of input electrodes and an output electrode, c. a transformer having 1. a core of substantially linear magnetic material having a closed magnetic path of approximately uniform cross-section with a small aperture introduced into said core to partition the magnetic cross section in a localized region into two branches between which the flux may be steered with a magnetomotive force, 2. a pair of primary power windings encircling the full core cross-section, each coupled between an output electrode of one of said semiconductor devices and said source terminals for generating an alternating flux in said core as said devices are switched, 3. a secondary power winding encircling the full core crosssection to derive an alternating voltage output, 4. first feedback winding means associated with said core and coupled to said input electrodes to provide self-regenerative feedback to each semiconductor device and cross-coupling between semiconductor devices to facilitate commutation; second feedback winding means associated with said core and coupled to said input electrodes to provide self-degenerative feedback to each semiconductor device; at least one of said feedback winding means being coupled through said aperture to one branch of said core to make the feedback dependent upon saturation of a partitioned branch.
Claim 3
Dependent Claim
40 words
a pair of primary power windings encircling the full core cross-section, each coupled between an output electrode of one of said semiconductor devices and said source terminals for generating an alternating flux in said core as said devices are switched,
Claim 4
Dependent Claim
40 words
a pair of primary power windings encircling the full core cross-section, each coupled between an output electrode of one of said semiconductor devices and said source terminals for generating an alternating flux in said core as said devices are switched,
Claim 5
Dependent Claim
81 words
A static inverter as set forth in claim 1 wherein a. said degenerative feedback winding means encircles one of said branches, b. a low resistance is provided sHunting said degenerative feedback winding means to induce a counter magneto-motive force to delay the magnetization of said one branch until saturation of said other branch but before full core saturation, said increasing degeneration offsetting the positive feedback to preclude full core saturation and thereby limit the maximum current demand on said semiconductor devices.
Claim 6
Dependent Claim
15 words
a secondary power winding encircling the full core cross-section to derive an alternating voltage output,
Claim 7
Dependent Claim
15 words
a secondary power winding encircling the full core cross-section to derive an alternating voltage output,
Claim 8
Dependent Claim
56 words
A static inverter as set forth in claim 2 wherein a pair of degenerative control transistors are provided each having a base electrode coupled to one of the ends of said degenerative feedback winding means, each of said control transistors being connected in shunt with the input electrode of a switching semiconductor device for degenerative control.
Claim 9
Dependent Claim
20 words
A static inverter as set forth in claim 3 wherein said one branch is less readily saturated than the other.
Claim 10
Dependent Claim
82 words
first feedback winding means associated with said core and coupled to said input electrodes to provide self-regenerative feedback to each semiconductor device and cross-coupling between semiconductor devices to facilitate commutation; second feedback winding means associated with said core and coupled to said input electrodes to provide self-degenerative feedback to each semiconductor device; at least one of said feedback winding means being coupled through said aperture to one branch of said core to make the feedback dependent upon saturation of a partitioned branch.
Claim 11
Dependent Claim
82 words
first feedback winding means associated with said core and coupled to said input electrodes to provide self-regenerative feedback to each semiconductor device and cross-coupling between semiconductor devices to facilitate commutation; second feedback winding means associated with said core and coupled to said input electrodes to provide self-degenerative feedback to each semiconductor device; at least one of said feedback winding means being coupled through said aperture to one branch of said core to make the feedback dependent upon saturation of a partitioned branch.
Claim 12
Dependent Claim
107 words
A static inverter as set forth in claim 1 wherein a. said degenerative winding means encircles one of said branches, and b. said regenerative feedback winding means encircles the other of said branches to terminate the regenerative feedback when said other branch saturates prior to full core saturation, and c. a low resistance is provided shunting said degenerative feedback winding means to induce a counter magneto-motive force to delay the magnetization of said one branch until saturation of said other branch but before full core saturation, said decreasing regeneration and increasing degeneration precluding full core saturation and thereby limiting the maximum current demand on said semiconductor devices.
Claim 13
Dependent Claim
50 words
A static inverter as set forth in claim 1 wherein a. said regenerative feedback winding means encircles one of said branches, b. said degenerative feedback winding means encircles the other of said branches, and c. both of said feedback winding means are of a few turns appropriate for current transformation.
Claim 14
Dependent Claim
95 words
A static inverter as set forth in claim 6 wherein a pair of auxiliary primary windings of a few turns appropriate for current transformation are provided encircling said other branch, each auxiliary winding being connected in series with one of said primary power windings between an output electrode of one of said semiconductor devices and said source terminal, each of said auxiliary windings being wound in the same sense as the primary winding in series therewith to generate a differential magneto-motive force diverting flux into said other branch, and to provide load current responsive feedback.
Claim 15
Dependent Claim
21 words
A static inverter as set forth in claim 7 wherein said one branch is less readily saturated than said other branch.
Claim 16
Dependent Claim
102 words
A static inverter as set forth in claim 7 wherein a pair of regenerative control transistors are provided, each having base, emitter and collector electrodes, the bases thereof being joined, the emitters being coupled to the respective ends of said regenerative winding means, and the collectors thereof being coupled respectively to an input electrode of one of said power switching devices, the serial input junctions of said regenerative control transistors providing a constant voltage load to said regenerative winding to establish a flux rate independent of inverter loading to insure prior saturation of said other branch, and to stabilize the oscillation frequency.
Claim 17
Dependent Claim
42 words
A static inverter as set forth in claim 9 wherein said power switching devices are transistors, each having base, emitter and collector electrodes, said emitter electrodes being common; said regenerative feedback, cross coupling and degenerative feedback being applied to said base electrodes.
Claim 18
Dependent Claim
48 words
A static inverter as set forth in claim 10 wherein a. said degenerative winding is coupled between the base electrodes of said switching transistors, and b. a pair of diodes are provided coupled between the ends of said degenerative winding and said common emitters, poled to provide commutation.
Claim 19
Dependent Claim
44 words
A static inverter as set forth in claim 11 wherein a pair of blocking diodes Are provided, each connected in series in the forward direction between the collector of one of said regenerative control transistors and the base of one of said switching transistors.
Claim 20
Dependent Claim
38 words
A static inverter as set forth in claim 12 wherein a pair of low valued resistances are provided in shunt with said regenerative control transistors to allow current to flow in said degenerative winding for low magneto-motive forces.
Claim 21
Dependent Claim
86 words
A static inverter as set forth in claim 13 wherein one additional pair of blocking diodes are provided, each connected in the forward direction between the collector of each switching transistor and one primary power winding and to block negative collector current, and a second additional pair of diodes are provided each coupling a respective winding end to said emitter common to provide an alternate path around said auxiliary primary winding and said switching transistor to any current blocked by diodes of said one additional pair.
Claim 22
Dependent Claim
59 words
A static inverter as set forth in claim 14 wherein a. an operating control winding of a few turns appropriate for current transformer action is provided encircling said other branch of said core, and b. means are provided for injecting a transient into said operating control winding to magnetize said path encircling said perforation momentarily to start inverter oscillation.
Claim 23
Dependent Claim
54 words
A static inverter as set forth in claim 15 wherein a. a turn-off transistor having a base electrode is provided shunting said operating control winding to preclude inverter oscillation when it is conductive, and b. means are provided for rendering said turn-off transistor non-conductive for a controlled operating period when said starting transient occurs.
Claim 24
Dependent Claim
53 words
A static inverter as set forth in claim 16 wherein a. said operating control winding is center tapped, and b. a pair of diodes are provided connected at the opposite ends thereof in series with said turn-off transistors and poled in the forward direction to permit turn-off during oscillatory swings of either polarity.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-10-20 | 1979-04-21 | 1979-10-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-20 | 1983-04-21 | 1983-10-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-20 | 1987-04-21 | 1987-10-21 | $7700.00 | Window Closed / Lapsed |